The history of the Last Supper is substantially the history of its restorations. It began to deteriorate very quickly, in fact, and steps were already being taken in the 16th century to try to limit the damage. This was primarily due to Leonardo's decision to use oils instead of the usual fresco technique whereby watercolours are applied on wet plaster. The surface or preparation on which they were applied, however, proved unsuitable because it was hygroscopic. Moisture from the air seeped through cracks in the colours into the underlying surface, which then started to swell and push off bits of the film of colours. Other events added to the damage. A doorway opened under the figure of Christ chopped off part of the picture. The room itself was used for some time as a stable and a billet for troops, and nails were driven into the walls. On 16 August 1943, an air raid during the second world war struck the convent and refectory was badly damaged. Its east wall collapsed completely, whereas the Last Supper was protected by a heavy tarpaulin that kept off the splinters. The explosion, however, widened the cracks that already existed. Earlier attempts at restoration had done far more harm than good. The worst and most invasive damage was caused in the 18th and 19th centuries. In 1725, the application of lye, potassium and oil paint ruined the surface. A coat of dark paint also sought to restore the picture's continuity. At the start of the 19th century, an attempt was made to detach the painting. The trials made for this purpose irremediably damaged Christ's right hand and removed a part of the tablecloth below Him. This was then replaced by painted wax.
THE CONSERVATIVE RESTORATION
The 20th century was marked by a move away from integrative to scientific and conservative restoration, starting with that undertaken by Mauro Pellicioli after 1943.
The latest restoration began in 1977 and was carried on until 1999 by Pinin Brambilla Barcilon, who set out to restore what remained of Leonardo's original coloured surface. This restoration has thus sapiently resuscitated sections and fragments of the original Leonardo, but has at the same time reduced the enjoyability of the scene as a whole, itself the fruit of subsequent integrations and therefore essentially false. Several features of the original painting have been recovered. Matthew (the third Apostle on the right), for example, is now redisplayed with a classical profile following the removal of a sort of beard that had been added to his chin. The floral decoration of the first arras to the left side on the wall beside the picture has been reinstated: a very delicate arrangement of flowers on a black field drawn from the motifs of choice fabrics. The folds of the tablecloth left by recent ironing - one of the aspects of the painting admired by its contemporaries - have been recovered. The colours of the clothes of the Apostles reflected on some plates and glasses, together with the reflection of a quarter of an orange on a pewter plate, have also been admirably brought back to a state very close to the original.
